Superposed well tubing assembly of separate tubing strings and method of supporting same



3,299,956 UBING Jan. 24, 1967 c. P. HOWE SUPEHPOSED WELL TUBING ASSEMBLYOF SEPARATE T STRINGS AND METHOD OF SUPPORTING SAME Filed July 8, 1964 2Sheets-Sheet 1 INVENTOR Char/es P Howe 7mdgm ATTORNEY Jan. 24, 1967 c.P. HOWE 3,299,956

SUPERPOSED WELL TUBING ASSEMBLY OF SEPARATE TUBING STRINGS AND METHOD OFSUPPORTING SAME 2 SheetsSheet 2 Filed July 8, 1964 INVENTOR Char/e5 PHowe ATTORNEY United States Patent Ofifice 3,299,956 Patented Jan. 24,1967 This application is a continuation-in-part of application SerialNo. 254,978 filed January 30, 1963, now Patent No. 3,105,719 ofSeptember 29, 1964.

This invention relates to a superposed well tubing string assembly in awell casing, and hook wall anchor means on string below the topmoststring supporting the weight of the string thereabove.

A further object of this invention is to provide a well tubing stringassembly wherein each string below the topmost string has mounted a'well slip hook wall anchor mounted on its top and actuated by theweight of a string thereabove into anchoring position to support theweight of the actuating string thereabove.

A further object of this invention is to provide a well tubing stringassembly, using the same hook wall anchor as that disclosed in the aboveidentified patent, but wherein the string assembly is a plurality ofseparate strings, with each string above the lowermost string supportedat its bottom on a wall anchor mounted at the top of the stringtherebelow, and the lowermost string supported by a mud anchor on thebottom of the well.

A further object of this invention is to provide a well tubing stringassembly, wherein each string of the assembly is made of suitablelength, possibly from 500 to 1,000 feet in length, and wherein theassembly may be 15,000 feet or more in length, wherein each stringsection is lowered or raised separately, and wherein the weight of eachstring assembly actuates a hook wall anchor mounted on the top of apreviously positioned lower string section to support the weight of theactuating string on the well casing, thus preventing excessive weightloads on the string sections and transferring the load of the strings tothe wall of the well casing.

A further object of this invention is to provide a methd of reducing theweight load on the tubing string by providing a plurality of separableand joinable string portions and supporting the weight of each separatesection at its bottom, the bottom string on the well bottom and theupper strings on the well casing wall.

A further object of this invention is to provide a method of reducingthe pumping load on the pumping equipment of a deep well by preservingthe bottom hole pressure within the pay zone and causing such pressureto lift oil within the tubing string to pumping equipment at the top ofthe string.

A further object is to provide an improved well slip assembly and alsoto provide an improved book wall assembly for a tubing string in a wellcasing.

A further object of this invention is to provide a well slip assemblymade in one piece thereby not only facilitating its manufacture, butgreatly facilitating its use in a hook wall anchor for releasablyanchoring a tubing string within a well casing so that it will supportthe weight of a pumping or tubing string thereabove, and which mayreadily be released from anchoring cooperation with the well casing whenit is desired to remove the pump or tubing string on which it is securedfrom the well casing, and wherein the anchor is released from the wellcasing before the weight of the tubing string there below is picked up,thus facilitating the lifting of the tubing string and its removal fromthe well casing.

Still a further object of this invention is to provide an improved wellslip assembly wherein there are a,

plurality of slip hooks, each integrally connected by a slip stemsubstantially narrower than the slip hook head, with the slip stemsextending integrally from a single integral column member in the generaldirection of the axis of the integral collar.

Still a further object of this invention is to provide a well slipassembly and hook anchor particularly useful in supporting the weight ofa tubing string supported thereabove.

Still a further object of this invention is to provide an improved wellslip assembly and hook wall anchor, particularly useful in multiplecompletion wells, in preventing excessive weight loads on productionequipment in deep wells and to assist in maintaining a controlledhydrostatic pressure and water flux as well as in other types of wells.

With the above and related objects in view, this invention consists inthe details of construction and combination of par-ts, as will be morefully understood from the following description, when read inconjunction with the accompanying drawing in which:

FIG. '1 is an elevational view of the hook wall anchor assembly andtubing string assembly of this invention in operative position in a wellcasing.

FIG. 2 is an enlarged detailed section in wall hook anchoring position.

FIG. 3 is a sectional view on line 33 of FIG. 2, showing the slip hookheads in anchored position.

FIG. 4 is a sectional view on line 44 of FIG. 2.

FIG. 5 is a partly sectional and partly elevational view of the hookassembly on the tubing string in non-anchoring position.

FIG. 6 is a continuation of the bottom of FIG. 5 on line A-A.

There is shown at 10 the well slip assembly which is used as a wall hookanchor on the top end of a tubing string 13 for supporting the weight ofa tubing string 13 or a topmost pumping string 12 on the wall of a wellcasing 16. Mounted on the top of each tubing string 13 is a mandrel 14,and this mandrel 14 is provided at its top with a beveled surface 17having a sealing O- ring 19 inserted therein. This beveled surface 17and O-ring 19 form a sealed joint with beveledsurface 21 on the bottomof a coupling 15 which is secured to the bottom tubing piece 65 of thestring thereabove. When the coupling 15 rests on the mandrel 14, theweight of the string thereabove actuates the well slip assembly 10 intosecuring position with the inside wall of the well casing 16 to supportthe weight of the string thereon on the wall of the well casing 16, aswill hereinafter become apparent.

The well slip assembly 10 per se consists of an integral collar 18 ofsuitable circumference from which integrally extends a plurality, hereshown as four, of slip stems 20 spaced from each other by spaces 22, thewidth of the spaces 22 being greater than the said circumferential widthof the stem 20, and at the upper end of each slip 20 there is provided aslip hook head 24.

Each hook slip head 24 is spaced from each adjacent hook head 24 by acomparatively narrow space 26 sufficient to permit the hook heads 24 toapproach each other when in non-holding position, and also permit oil toflow thereby when in holding position. As will be apparent from FIGS. 3and 4, the slip stems 20 and hook heads 24 are annular in cross section,generally having the same circumference, when in relaxed nonholdingposition, as the slip assembly collar 18.

On the inner surface of each hook head 24, a tapering surface 28 isprovided from a point 30 intermediate the attached end 32 and free end34 of each hook head, this surface 28 tapering outwardly. The outersurface of each hook head 24 is provided with a plurality of parallelcircumferential hook ridges 36 shaped approximately as shown. It will beobserved that each hook ridge 36 has a long surface 38 approximately atright angles with a short surface 40, thus providing a sharp edge 42which provides the gripping hook portion thereof in cooperating with thewell casing 16 when the hook head 24 is forced or wedged into contacttherewith by a complementary tapered surface 44 on the mandrel 14.

In operation, when the mandrel 14 has its tapered surface 44 pusheddownwardly by the weight of the string 12 or 13 thereabove into wedgingaction within the hook heads 24, the hook heads 24 are wedged outwardlyinto anchoring position with the well casing 16, as clearly illustratedin FIG. 2 and FIG. 3.

The coupling 15 is connected in a conventional manner =by threads to thebottom end piece 65 of pumping string 12 or tubing string 13. Thepumping string 12 is of conventional construction in which there islocated the usual pump head 23 and packing assembly 25 and to whichthere extends the pumping rod 27 connected thereabove to the usualsucker rod, the same being of conventional details, one illustration ofwhich is shown in applicants prior patents, Numbered 2,674,- 198 and2,674,200, and copending and now issued Patents 3,150,605 and 3,150,606of September 29, 1964.

Depending from the mandrel 14 is an assembly tube 48 forming part of thetubing string 13, the assembly tube 48 extending slidably down throughthe packing collar 50 and the packing assembly 52 with its packing 54,the assembly tube 48 terminating in an enlarged shouldered end 56 havinga shoulder 58, the shoulder 58 being of a size to abut against thebottom of the packing assembly 52, as shown in FIG. 6, while theshouldered end 56 can slide down or up freely in an assembly tubing 60.As will be observed in FIGS. and 6, the well slip assembly slides freeon the assembly tube 50 between the bottom of the tapered end 44 ofmandrel 14 and the top of packing assembly 52.

The strings 12 and 13 each includes as many couplings and/or adapters 62and 64 and as many tubing pieces 65 as necessary to make up the desiredlength of each pump or tubing string 12 or 13. In the pumping string 12,the pumping barrel 66, containing the usual working barrel, pump valveand standing valve, such as more particularly illustrated in theaforementioned Howe Patents Nos. 2,674,198 and 2,674,200, is dependentfrom the pump head 23 which is sealed by the packing 25 to the insidewall of the well casing so that no fluid may pass in either directionbetween the well casing and the pump head, as shown in these lattermentioned Howe patents. The string sealing coupling is secured on thebottom end of the lowermost string piece 65, except for the lowermoststring 13 at the bottom of the well. The bottom tubing piece 65 of thislowermost string is provided with a perforated mud anchor 68 connectedthereto by suitable couplings 70. The length of the lowermost string 13may be fairly short of small weight and the mud anchor is of sufficientlength to guarantee that enough of its perforations 72 will alwaysremain above the well bottom 74 so that oil which has entered throughthe perforations 76 in casing 16 located above the pay zone or oil sandof the well may enter the mud anchor perforations and ascend within thetubing strings 13 to the pumping string 12 and be pumped therefrom bythe pump therewithin. Oil and gas pressure from the pay zone may ascendwithin the casing 16 about the strings 12 and 13 until it reaches aheight to counterbalance the gas pressure of the well against thepacking 25. This oil and gas pressure forces oil through the mud anchorperforations 72 into the inside of the tubing strings 13 and pumpingstring 12 to be pumped therefrom by the pump therein to the top of thewell.

The lowermost string 13 of suitable short length, with its mud anchor 68is first inserted in the casing 16 until it rests on the bottom 74 ofthe well, the string 13 being lowered on a fish, as usual, the fishbeing temporarily secured to the internal threads. Then the next stringis inserted in the same manner, and the coupling 15 on the bottom of thenext string has its beveled bottom 17 squeeze the O-ring 19 into asealing contact with the top beveled surface of the mandrel 14 thusproviding a mating, sealed joint that is readily and non-rotatablymakable and separable in a vertical direction, as it forces the mandrel14 downwardly into the well slip assembly 10 to cause the well slipanchor hook heads 24 to secure themselves firmly to the inside wall ofthe well casing 16 as set forth in detail above, and thus support theweight of the string 13 thereabove. This is repeated with eachsuccessive string 13 so that the weight of the strings above the lowestone is carried by the well casing. Then, the topmost string, the pumpingstring 12, is placed in position, and the packing assembly 25 is sealedagainst the casing, as described in the aforementioned Howe patents.

If it is necessary to remove the pumping string and/ or the tubingstrings, the oil and sand above the pumping head is released through thedrain valve forming :part of the pump head 23, as described in thelatter mentioned Howe patents, then the packing 25 is released, as inthese same patents, whereupon the pumping string 12 may be readilylifted from the well casing 16. A- fish is placed into the threads '78of the mandrel 14, permitting it to be raised to first release the hookheads 24 from the well casing 16, and then to raise the string 13, andthe same procedure is repeated with each lower string until all havebeen removed if desired.

This invention serves to prevent excessive weight loads on productionequipment in deep wells. Some deep wells are skimmed from a point up thehole to prevent excessive weight loads on the production equipment. Whenthis is accomplished with conventional equipment, water accumulates inthe bottom of the well, restricting the produc tion. When thisrestriction in production occurs, it becomes necessary to pull the welland swab or bail the water from the well bore. By running tubing to thebottom and setting the hook wall to support each string thereon on thecasing wall, excessive weight loads on the production equipment andaccumulation of water in the bottom of the well are prevented.

This equipment, as described, also serves to maintain a controlledhydrostatic pressure in water floods. In some water flood projects, itis necessary to maintain certain hydrostatic back pressure on theformation to force the water through the less permeable portion of thesand, or to prevent it from channeling through previously flooded areasof the reservoir.

With the strings and wall anchor hooks of this equipment, this isacomplished by sealing the pumping tubing to the well casing at acalculated point in the well to maintain the desired back pressure.

This invention has thus provided both an improved slip assembly and animproved hook wall anchor utilizing such Islip assembly and usea'ble insolving different Well probems.

In the drawings, like numbers refer to like parts, and for the purposesof explication, set forth below are the numbered parts of the improved'Superposed Well Tubing Assembly, and the like:

well slip assembly 12 pumping string 13 tubing string 14 mandrel 15coupling at bottom of strings 16 well casing 17 bevel on top of 14 a 18slip assembly collar 19 O-ring in 17 20 slip stem 21 bevel on bottom of15 22 spaces between stems 20 23 pump head I 24 slip hook head 25packing assembly 26 spaces between hook heads 24 27 pump rod 28 internaltaper on hook head 24 30 point where taper 28 begins 32 attached end ofhook head 24 34 free end of hook head 24 36 hook ridges 38 long side ofridges 36 40 short side of ridges 36 42 hook point or edge of ridges '3644 external taper on mandrel 14 46 coupling between mandrel 14 andpumping string piece 65 48 assembly tube threadedly secured to bottom ofmandrel 14 50 packing collar of packing assembly 52 52 packing assembly54 packing in assembly 52 56 shouldered end of assembly tube 50 58shoulder on end 56 '60 assembly barrel secured to packing assembly 52 62coupling for barrel 60 to adapter 64 64 adapter 65 tubing pieces 66 pumpbarrel in pumping string 12 68 mud anchor at bottom 70 couplings betweenmud anchor 68 and lowermost string tubing piece 65 72 perforations inmud anchor 68 74 oil well bottom 76 oil entrance perforations in wellcasing 16 78 fish receiving threads in mandrel 14 Although thisinvention has been described in considerable detail, such description isintended as being illustrative rather than limiting, since the inventionmay .be variously embodied, and the scope of the invention is to bedetermined as claimed.

Having thus set forth and disclosed the nature of this invention, whatis claimed is:

1. A well pumping assembly comprising a well casing, a plurality ofsuperposed individually separate strings of tubing sealingly engagingeach other inside said casing, the joining ends of said stringsproviding a mating sealed joint readily and non-rotatably separable in avertical direction, and means for supporting each tubing string at itsbottom, said means including means on each string, except the topmoststring, engageable with the well casing for supporting the weight of theindividual string thereabove.

2. The assembly of claim 1, said string supporting means for thelowermost string comprising a mud anchor on the bottom end of saidlowermost string arranged to be supported on the bottom of the well andthus carry the weight of the lowermost string.

3. The assembly of claim 1, said string supporting 6 means for eachsuperposed string comprising a hook wall anchor mounted on the top endof each string below the topmost string and arranged to be activatedinto anchoring position by the weight of the string thereabove restingthereon to thereby support the weight of the string thereabove, saidtopmost string being a pump string.

4. The assembly of claim 2, said string supporting means for eachsuperposed string comprising a hook wall anchor mounted on the top endof each string below the topmost string and arranged to be activatedinto anchoring position by the weight of the string thereabove restingthereon to thereby support the weight of the string thereabove, saidtopmost string being a pump string.

5. The assembly of claim 4 in combination with a pumping barrel andstanding valve, said barrel and standing valve being located in saidtopmost pump string and above the topmost hook wall anchor.

6. The assembly of claim 5, each said hook wall anchor comprising a wellslip assembly collar, a plurality of circumferentially spaced apart slipstems integrally extending at one end from said collar in the generaldirection of the axis of said collar, and a slip hook head integrallyextending from the other end of said slip stem, the inner surface ofeach said hook head tapering toward its unattached end, in combinationwith a mandrel mounted in the tubing string adjacent to the tapered endsof each said slip hook heads, said mandrel being externally taperedcomplementary to the internal taper on said hook heads, each saidmandrel being manipulable by the weight of the string thereabove toinsert its externally tapered surface against the internal taperedsurfaces of said slip hook heads to wedge said slip hook heads intoanchoring position into the inner surface of the well casing to thussupport the weight of the string thereabove on the well casing.

7. A superposed well tubing string assembly comprising a plurality ofindividual separate superposed tubing strings having their joining endsproviding a mating sealed joint readily and non-rotatably separable in avertical direction, and well casing wall anchor means mounted on the topof each separate tubing string below the topmost pump string, each saidwell casing wall anchor means being engageable with a well casing forsupporting the weight of the individual separate tubing stringthereabove.

8. The method of reducing the pumping load in a deep well comprisingextending a well casing to below the pay zone, the casing having oilentrance perforations below the pay zone, vertically and non-rotatablyinserting separate, joinable tubing strings having contacting andsealing mating string ends into the inserted wall casing, resting thelowermost string on the well bottom, the lowermost string having oilentrance perforation means adjacent its bottom, anchoring the top ofeach string except the topmost string to the well casing to therebysupport the separate string thereabove on the well casing wall,providing a pumping string as the topmost string, and sealing thetopmost string to the well casing Wall at -a point adjacent the top ofsuch topmost string, thereby preserving the bottom hole pressure in thewell to build up pressure between the well casing and the tubing andthus cause such pressure to lift oil within the tubing to the pumpingstring tubing.

9. The method of reducing the weight load of pumping equipment on thetubing string in a deep well comprising installing a well casingperforated below the pay zone, inserting a short tubing string having amud anchor resting on the well bottom and having a well slip hook wallanchor and actuating mandrel at its top, the mandrel having a sealedjoint forming surface at its top, successively vertically andnon-rotatably inserting further separate strings, each further stringhaving a mandrel actuating joint cooperating mating coupling at itsbottom and a similar well slip and actuating mating mandrel at its top,and then a pumping string at the top with a similar bottom matingcoupling, whereby each separate upper string actuates the well slip hookwall anchor of the string therebelow to support the weight of theseparate upper string on the well casing, and then sealing the pumpingstring at its top to the well casing .to prevent oil flow therebybetween the pumping string and the casing.

10. The method of reducing the weight load of pumping equipment on thetubing string in a deep well comprising providing a top pumping stringand lower tubing strings in the form of a plurality of se arate joinablestrings, supporting the bottom string on the Well bottom, providing aWell casing hook wall anchor and actuating mating mandrel at the top ofeach string except the top string and a scalable mating coupling at thebottom of each string except the bottom string, actuating each anchor bythe Weight of the string thereabove by vertically and nonrotatablyplacing the sealable mating coupling of an upper string on the actuatingmandrel of a lower string to simultaneously seal the upper string to thelower string and support the weight of the upper string through theactuated anchor on the well casing wall, and sealing the pumping stringto the well casing wall adjacent the upper end of the pumping string.

References Cited by the Examiner UNITED STATES PATENTS 2,188,656 1/1940Giberson 166216X 5 2,720,844 10/1955 Bodine 103 219 2,982,355 5/1961Rodgers 166 105 3,119,450 1/1964 Evans 166-119 3,170,518 2/1965 Brown166119 References Cited by the Applicant UNITED STATES PATENTS 2,345,8884/1944 Scott. 2,674,198 4/1954 Howe. 2,675,200 4/1954 Howe. 15 2,708,0015/1955 Reed.

2,982,355 5/1961 Rodgers. 3,097,697 7/1963 States.

CHARLES E. OCONNELL, Primary Examiner. 20 J. A. LEPPINK, AssistantExaminer.

1. A WELL PUMPING ASSEMBLY COMPRISING A WELL CASING, A PLURALITY OFSUPERPOSED INDIVIDUALLY SEPARATE STRINGS OF TUBING SEALINGLY ENGAGINGEACH OTHER INSIDE SAID CASING, THE JOINING ENDS OF SAID STRINGSPROVIDING A MATING SEALED JOINT READILY AND NON-ROTATABLY SEPARABLE IN AVERTICAL DIRECTION, AND MEANS FOR SUPPORTING EACH TUBING STRING AT ITSBOTTOM, SAID MEANS INCLUDING MEANS ON EACH STRING, EXCEPT THE TOPMOSTSTRING, ENGAGEABLE WITH THE WELL CASING FOR SUPPORTING THE WEIGHT OF THEINDIVIDUAL STRING THEREABOVE.
 8. THE METHOD OF REDUCING THE PUMPING LOADIN A DEEP WELL COMPRISING EXTENDING A WELL CASING TO BELOW THE PAY ZONE,THE CASING HAVING OIL ENTRANCE PERFORATIONS BELOW THE PAY ZONE,VERTICALLY AND NON-ROTATABLY INSERTING SEPARATE, JOINABLE TUBING STRINGSHAVING CONTACTING AND SEALING MATING STRING ENDS INTO THE INSERTED WALLCASING, RESTING THE LOWERMOST STRING ON THE WELL BOTTOM, THE LOWERMOSTSTRING HAVING OIL ENTRANCE PERFORATION MEANS ADJACENT ITS BOTTOM,ANCHORING THE TOP OF EACH STRING EXCEPT THE TOPMOST STRING TO THE WELLCASING TO THEREBY SUPPORT THE SEPARATE STRING THEREABOVE ON THE WELLCASING WALL, PROVIDING A PUMPING STRING AS THE TOPMOST STRING, ANDSEALING THE TOPMOST STRING TO THE WELL CASING WALL AT A POINT ADJACENTTHE TOP OF SUCH TOPMOST STRING, THEREBY PRESERVING THE BOTTOM HOLEPRESSURE IN THE WELL TO BUILD UP PRESSURE BETWEEN THE WELL CASING ANDTHE TUBING AND THUS CAUSE SUCH PRESSURE TO LIFT OIL WITHIN THE TUBING TOTHE PUMPING STRING TUBING.